This invention relates to a method and apparatus for the continuous production of quaternized N,N-dialkylaminoethyl (meth)acrylates (DMAEA.MCQ).
DMAEA.MCQDMAEA.MCQ is an important monomer intermediate used in producing cationic flocculant polymers. It is known that DMAEA.MCQ can be produced by reacting N,N-dimethylaminoethyl acrylate (DMAEA) under various conditions. A good method of synthesizing DMAEA is described in U.S. patent application Ser. No. 12/468,585. An efficient method of producing DMAEA.MCQ from DMAEA would involve a continuous synthesis, which avoids the burdensome and costly start and stop mechanics inherent in batch type production methods.
A number of unsatisfactory methods have previously been developed to produce DMAEA.MCQ from DMAEA. Japanese Patent Applications 2003/342244, 2004/010508, and 2004/155669 use continuously stirred tank reactors (CSTR) connected in series to continuously produce DMAEA.MCQ. Their preference for multiple reactors however is cumbersome and expensive. Japanese patent application 1995/206790 describes conducting the synthesis in a thin film evaporator reactor. This method unfortunately uses equipment that is typically associated with higher operating costs in comparison with the present invention. U.S. Pat. No. 6,683,203 uses a rotating disc agitated column design but suffers from an unduly long residence time. Chinese patent applications CN 1296942 and CN 1276367 use tower reactors to produce DMAEA.MCQ but are also less than ideal.
Thus there is clear need and utility for an improved method of continuously and efficiently producing DMAEA.MCQ. The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists.